Switch syscall(2)/__syscall(2) calls to libc calls on NetBSD

[krytarowski]

Summary

When possible, switch syscall(2)/__syscall(2) calls
to direct calls of internal libc symbols.

Add a new function to detect address of a libc
symbol of a function that could be intercepted.
With the address detector in GetRealLibcAddress(),
an optional interceptor of libc call will be bypassed.

The original approach with syscall(2)/__syscall(2)
wasn't portable across supported ABIs and CPU
architectures. The indirect syscall interface is
also a candidate for removal in future revisions
of NetBSD, as the C language ABI is not a good
domain for serialization of arbitrary functions
arguments.

Switch the following functions to libc calls:

• internal_mmap()
• internal_munmap()
• internal_mprotect()
• internal_close()
• internal_open()
• internal_read()
• internal_write()
• internal_ftruncate()
• internal_stat()
• internal_lstat()
• internal_fstat()
• internal_dup2()
• internal_readlink()
• internal_unlink()
• internal_rename()
• internal_sched_yield()
• internal__exit()
• internal_sleep()
• internal_execve()
• NanoTime()
• internal_clock_gettime()
• internal_waitpid()
• internal_getpid()
• internal_getppid()
• internal_getdents()
• internal_lseek()
• internal_sigaltstack()
• internal_fork()
• internal_sigprocmask()
• internal_sysctl()
• internal_sigemptyset()
• internal_sigfillset()
• GetTid()
• TgKill()

This revision leaves room for refactoring in subsequent commits.

[devnexen]

Just curious, any impact in term of performance ?

[krytarowski]

In D51419#1217377, @devnexen wrote:

Just curious, any impact in term of performance ?

There might be some impact, but it's negligible (and not necessarily slower). We exchange overhead of deserialization of a syscall in syscall(2)/__syscall(2) (on the kernel side) for overhead of calling a libc gateway to the real syscall through a function pointer.

This change is also needed for future planned changes such as addition of internal_sysctl*() and adding interceptors for sysctl*().
Without switch to libc it's harder to get it done sanely, as we have got additional special cases such as sysctlbyname(3) reimplemented for the use of rumpkernels.

There are no regressions observed (on NetBSD) with this commit.

[joerg]

I don't understand why most of this symbols don't reference the plain system call directly, i.e. _sys_read etc.

[krytarowski]

_sys_ seems to be available only for a small set of of system calls and is not universal.

$ nm /usr/lib/libc.so|grep _sys_|wc -l
64

I can switch these ones (read, write, close, readlink, sched_yield and wait4 for waitpid), but why?

[krytarowski]

Personally, I prefer to go for public symbols as with next major libc bump, they might stay around. So not depend too much on the internals that shall be rather not used by 3rd party software.

[krytarowski]

OK, it looks like these ones are cancel points. I will switch them to _sys_.

[joerg]

Every system call has a public and internal variant. The former might be replaced by libpthread etc for thread cancellation support, but that's a different topic.

[krytarowski]

What's the internal variant for e.g. dup2(2) or getpid(2)?

[krytarowski]

When possible, switch indirect calls to direct calls of internal libc symbols.

[krytarowski]

ping?

[vitalybuka]

Now SANITIZER_NETBSD shares almost nothing with the rest
May I ask you to create sanitizer_netbsd.cc and move code there?

lib/sanitizer_common/sanitizer_linux.cc

204

This is very similar to GetRealFunctionAddress from interception/interception_linux.cc

Maybe just use DEFINE_REAL with INTERCEPT_FUNCTION?

[krytarowski]

In D51419#1224011, @vitalybuka wrote:

Now SANITIZER_NETBSD shares almost nothing with the rest
May I ask you to create sanitizer_netbsd.cc and move code there?

I will do it!

lib/sanitizer_common/sanitizer_linux.cc

204

I saw this, but I wasn't sure how to do it. The existing macros are designed to install interceptors, and in my case I'm performing the opposite operation.

[vitalybuka]

I will do it!

I assume work in progress?

[krytarowski]

I have been preempted by a conference EuroBSDCon 2018 in Bucharest, Romania.

I had two talks there (1. Userland sanitizers in NetBSD 2. Kernel sanitizers in NetBSD)

http://netbsd.org/~kamil/eurobsdcon2018_sanitizers.html
http://netbsd.org/~kamil/eurobsdcon2018_ksanitizers.html

I'm going to adapt the patch soon and submit to review.

[vitalybuka]

no pressure, just removing from my "Ready to Review" list

[krytarowski]

Extract NetBSD specific code from common linux.cc to newly created netbsd.cc file.

[krytarowski]

Improve code comments.

[krytarowski]

I will introduce code fixups and cleanups after getting this merged.

[devnexen]

lib/sanitizer_common/sanitizer_netbsd.cc

107

Would it need check too ?

[krytarowski]

• add CHECK()
• add forgotten TgKill()

[krytarowski]

• reduce code duplication with addition of helper macros

[vitalybuka]

lib/sanitizer_common/sanitizer_linux.cc

240

For this patch I see "Context not available."
Probably it was not created with arc tool.

708–710

for future refactoring it would be nice to collect all non-NETBSD stuff into single #if !SANITIZER_NETBSD

lib/sanitizer_common/CMakeLists.txt

   sanitizer_linux.cc
   sanitizer_linux_s390.cc
   sanitizer_mac.cc
+  sanitizer_netbsd.cc
   sanitizer_openbsd.cc
   sanitizer_persistent_allocator.cc
   sanitizer_platform_limits_linux.cc

lib/sanitizer_common/sanitizer_linux.cc

 #include <asm/param.h>
 #endif
 
-#if SANITIZER_NETBSD
-#include <lwp.h>
-#endif
-
 // For mips64, syscall(__NR_stat) fills the buffer in the 'struct kernel_stat'
 // format. Struct kernel_stat is defined as 'struct stat' in asm/stat.h. To
 // access stat from asm/stat.h, without conflicting with definition in

 #endif
 
 // --------------- sanitizer_libc.h
-#if !SANITIZER_SOLARIS
+#if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
 #if !SANITIZER_S390 && !SANITIZER_OPENBSD
 uptr internal_mmap(void *addr, uptr length, int prot, int flags, int fd,
                    OFF_T offset) {
-#if SANITIZER_NETBSD
-  return internal_syscall64(SYSCALL(mmap), addr, length, prot, flags, fd,
-                              (long)0, offset);
-#elif SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
+#if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
   return internal_syscall(SYSCALL(mmap), (uptr)addr, length, prot, flags, fd,
                           offset);
 #else

 
 uptr internal_ftruncate(fd_t fd, uptr size) {
   sptr res;
-#if SANITIZER_NETBSD
-  HANDLE_EINTR(res, internal_syscall64(SYSCALL(ftruncate), fd, 0, (s64)size));
-#else
   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(ftruncate), fd,
                (OFF_T)size));
-#endif
   return res;
 }
 

 #endif
 
 uptr internal_stat(const char *path, void *buf) {
-#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD
+#if SANITIZER_FREEBSD || SANITIZER_OPENBSD
   return internal_syscall_ptr(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf,
                               0);
 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS

 }
 
 uptr internal_lstat(const char *path, void *buf) {
-#if SANITIZER_NETBSD
-  return internal_syscall_ptr(SYSCALL(lstat), path, buf);
-#elif SANITIZER_FREEBSD || SANITIZER_OPENBSD
+#if SANITIZER_FREEBSD || SANITIZER_OPENBSD
   return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf,
                           AT_SYMLINK_NOFOLLOW);
 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS

 }
 
 uptr internal_fstat(fd_t fd, void *buf) {
-#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD ||              \
+#if SANITIZER_FREEBSD || SANITIZER_OPENBSD || \
     SANITIZER_LINUX_USES_64BIT_SYSCALLS
-#if SANITIZER_MIPS64 && !SANITIZER_NETBSD && !SANITIZER_OPENBSD
+#if SANITIZER_MIPS64 && !SANITIZER_OPENBSD
   // For mips64, fstat syscall fills buffer in the format of kernel_stat
   struct kernel_stat kbuf;
   int res = internal_syscall(SYSCALL(fstat), fd, &kbuf);

 }
 
 void internal__exit(int exitcode) {
-#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD
+#if SANITIZER_FREEBSD || SANITIZER_OPENBSD
   internal_syscall(SYSCALL(exit), exitcode);
 #else
   internal_syscall(SYSCALL(exit_group), exitcode);

   return internal_syscall_ptr(SYSCALL(execve), (uptr)filename, (uptr)argv,
                               (uptr)envp);
 }
-#endif // !SANITIZER_SOLARIS
+#endif  // !SANITIZER_SOLARIS && !SANITIZER_NETBSD
 
 // ----------------- sanitizer_common.h
 bool FileExists(const char *filename) {

   return S_ISREG(st.st_mode);
 }
 
+#if !SANITIZER_NETBSD
 tid_t GetTid() {
 #if SANITIZER_FREEBSD
   long Tid;

   return Tid;
 #elif SANITIZER_OPENBSD
   return internal_syscall(SYSCALL(getthrid));
-#elif SANITIZER_NETBSD
-  return _lwp_self();
 #elif SANITIZER_SOLARIS
   return thr_self();
 #else

 #elif SANITIZER_OPENBSD
   (void)pid;
   return internal_syscall(SYSCALL(thrkill), tid, sig, nullptr);
-#elif SANITIZER_NETBSD
-  (void)pid;
-  return _lwp_kill(tid, sig);
 #elif SANITIZER_SOLARIS
   (void)pid;
   return thr_kill(tid, sig);
 #endif
 }
+#endif
 
-#if !SANITIZER_SOLARIS
+#if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
 u64 NanoTime() {
-#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD
+#if SANITIZER_FREEBSD || SANITIZER_OPENBSD
   timeval tv;
 #else
   kernel_timeval tv;

 uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp) {
   return internal_syscall_ptr(SYSCALL(clock_gettime), clk_id, tp);
 }
-#endif // !SANITIZER_SOLARIS
+#endif  // !SANITIZER_SOLARIS && !SANITIZER_NETBSD
 
 // Like getenv, but reads env directly from /proc (on Linux) or parses the
 // 'environ' array (on some others) and does not use libc. This function
 // should be called first inside __asan_init.
 const char *GetEnv(const char *name) {
-#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD ||              \
+#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD || \
     SANITIZER_SOLARIS
   if (::environ != 0) {
     uptr NameLen = internal_strlen(name);

 // The actual size of this structure is specified by d_reclen.
 // Note that getdents64 uses a different structure format. We only provide the
 // 32-bit syscall here.
-#if SANITIZER_NETBSD || SANITIZER_OPENBSD
+#if SANITIZER_NETBSD
+// Not used
+#elif SANITIZER_OPENBSD
 // struct dirent is different for Linux and us. At this moment, we use only
 // d_fileno (Linux call this d_ino), d_reclen, and d_name.
 struct linux_dirent {

 };
 #endif
 
-#if !SANITIZER_SOLARIS
+#if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
 // Syscall wrappers.
 uptr internal_ptrace(int request, int pid, void *addr, void *data) {
-#if SANITIZER_NETBSD
-  // XXX We need additional work for ptrace:
-  //   - for request, we use PT_FOO whereas Linux uses PTRACE_FOO
-  //   - data is int for us, but void * for Linux
-  //   - Linux sometimes uses data in the case where we use addr instead
-  // At this moment, this function is used only within
-  // "#if SANITIZER_LINUX && defined(__x86_64__)" block in
-  // sanitizer_stoptheworld_linux_libcdep.cc.
-  return internal_syscall_ptr(SYSCALL(ptrace), request, pid, (uptr)addr,
-                              (uptr)data);
-#else
   return internal_syscall(SYSCALL(ptrace), request, pid, (uptr)addr,
                           (uptr)data);
-#endif
 }
 
 uptr internal_waitpid(int pid, int *status, int options) {

 }
 
 uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
-#if SANITIZER_NETBSD
-  return internal_syscall64(SYSCALL(lseek), fd, 0, offset, whence);
-#else
   return internal_syscall(SYSCALL(lseek), fd, offset, whence);
-#endif
 }
 
 #if SANITIZER_LINUX

 #endif
 }
 
-#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD
+#if SANITIZER_FREEBSD || SANITIZER_OPENBSD
 int internal_sysctl(const int *name, unsigned int namelen, void *oldp,
                     uptr *oldlenp, const void *newp, uptr newlen) {
 #if SANITIZER_OPENBSD

 
 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
                           __sanitizer_sigset_t *oldset) {
-#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD
+#if SANITIZER_FREEBSD || SANITIZER_OPENBSD
   return internal_syscall_ptr(SYSCALL(sigprocmask), how, set, oldset);
 #else
   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;

   return k_set->sig[idx] & (1 << bit);
 }
 #endif  // SANITIZER_LINUX
-#endif // !SANITIZER_SOLARIS
+#endif  // !SANITIZER_SOLARIS && !SANITIZER_NETBSD
 
+#if !SANITIZER_NETBSD
 // ThreadLister implementation.
 ThreadLister::ThreadLister(pid_t pid) : pid_(pid), buffer_(4096) {
   char task_directory_path[80];

   if (!internal_iserror(descriptor_))
     internal_close(descriptor_);
 }
+#endif
 
 #if SANITIZER_WORDSIZE == 32
 // Take care of unusable kernel area in top gigabyte.

lib/sanitizer_common/sanitizer_netbsd.cc

+//===-- sanitizer_linux.cc ------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is shared between Sanitizer run-time libraries and implements
+// NetBSD-specific functions from sanitizer_libc.h.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_platform.h"
+
+#if SANITIZER_NETBSD
+
+#include "sanitizer_common.h"
+#include "sanitizer_flags.h"
+#include "sanitizer_getauxval.h"
+#include "sanitizer_internal_defs.h"
+#include "sanitizer_libc.h"
+#include "sanitizer_linux.h"
+#include "sanitizer_mutex.h"
+#include "sanitizer_placement_new.h"
+#include "sanitizer_procmaps.h"
+
+#include <sys/param.h>
+#include <sys/types.h>
+
+#include <sys/exec.h>
+#include <sys/mman.h>
+#include <sys/ptrace.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/sysctl.h>
+#include <sys/time.h>
+
+#include <dlfcn.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <link.h>
+#include <lwp.h>
+#include <pthread.h>
+#include <sched.h>
+#include <signal.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+extern "C" void *__mmap(void *, size_t, int, int, int, int,
+                        off_t) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" int __sysctl(const int *, unsigned int, void *, size_t *,
+                        const void *, size_t) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" int _sys_close(int) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" int _sys_open(const char *, int, ...) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" ssize_t _sys_read(int, void *, size_t) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" ssize_t _sys_write(int, const void *,
+                              size_t) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" int __ftruncate(int, int, off_t) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" ssize_t _sys_readlink(const char *, char *,
+                                 size_t) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" int _sys_sched_yield() SANITIZER_WEAK_ATTRIBUTE;
+extern "C" int _sys___nanosleep50(const void *,
+                                  void *) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" int _sys_execve(const char *, char *const[],
+                           char *const[]) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" off_t __lseek(int, int, off_t, int) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" int __fork() SANITIZER_WEAK_ATTRIBUTE;
+extern "C" int _sys___sigprocmask14(int, const void *,
+                                    void *) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" int _sys___wait450(int wpid, int *, int,
+                              void *) SANITIZER_WEAK_ATTRIBUTE;
+
+namespace __sanitizer {
+
+static void *GetRealLibcAddress(const char *symbol) {
+  void *real = dlsym(RTLD_NEXT, symbol);
+  if (!real)
+    real = dlsym(RTLD_DEFAULT, symbol);
+  if (!real) {
+    Printf("GetRealLibcAddress failed for symbol=%s", symbol);
+    Die();
+  }
+  return real;
+}
+
+#define _REAL(func, ...) real##_##func(__VA_ARGS__)
+#define DEFINE__REAL(ret_type, func, ...)                              \
+  static ret_type (*real_##func)(__VA_ARGS__) = NULL;                  \
+  if (!real_##func) {                                                  \
+    real_##func = (ret_type(*)(__VA_ARGS__))GetRealLibcAddress(#func); \
+  }                                                                    \
+  CHECK(real_##func);
+#define DEFINE_INTERNAL(ret_type, func, ...) \
+  ret_type internal_##func(__VA_ARGS__)
+
+// --------------- sanitizer_libc.h
+DEFINE_INTERNAL(uptr, mmap, void *addr, uptr length, int prot, int flags,
+                int fd, OFF_T offset) {
+  CHECK(&__mmap);
+  return (uptr)__mmap(addr, length, prot, flags, fd, 0, offset);
+}
+
+DEFINE_INTERNAL(uptr, munmap, void *addr, uptr length) {
+  DEFINE__REAL(int, munmap, void *a, uptr b);
+  return _REAL(munmap, addr, length);
+}
+
+DEFINE_INTERNAL(int, mprotect, void *addr, uptr length, int prot) {
+  DEFINE__REAL(int, mprotect, void *a, uptr b, int c);
+  return _REAL(mprotect, addr, length, prot);
+}
+
+DEFINE_INTERNAL(uptr, close, fd_t fd) {
+  CHECK(&_sys_close);
+  return _sys_close(fd);
+}
+
+DEFINE_INTERNAL(uptr, open, const char *filename, int flags) {
+  CHECK(&_sys_open);
+  return _sys_open(filename, flags);
+}
+
+DEFINE_INTERNAL(uptr, open, const char *filename, int flags, u32 mode) {
+  CHECK(&_sys_open);
+  return _sys_open(filename, flags, mode);
+}
+
+DEFINE_INTERNAL(uptr, read, fd_t fd, void *buf, uptr count) {
+  sptr res;
+  CHECK(&_sys_read);
+  HANDLE_EINTR(res, (sptr)_sys_read(fd, buf, (size_t)count));
+  return res;
+}
+
+DEFINE_INTERNAL(uptr, write, fd_t fd, const void *buf, uptr count) {
+  sptr res;
+  CHECK(&_sys_write);
+  HANDLE_EINTR(res, (sptr)_sys_write(fd, buf, count));
+  return res;
+}
+
+DEFINE_INTERNAL(uptr, ftruncate, fd_t fd, uptr size) {
+  sptr res;
+  CHECK(&__ftruncate);
+  HANDLE_EINTR(res, __ftruncate(fd, 0, (s64)size));
+  return res;
+}
+
+DEFINE_INTERNAL(uptr, stat, const char *path, void *buf) {
+  DEFINE__REAL(int, __stat50, const char *a, void *b);
+  return _REAL(__stat50, path, buf);
+}
+
+DEFINE_INTERNAL(uptr, lstat, const char *path, void *buf) {
+  DEFINE__REAL(int, __lstat50, const char *a, void *b);
+  return _REAL(__lstat50, path, buf);
+}
+
+DEFINE_INTERNAL(uptr, fstat, fd_t fd, void *buf) {
+  DEFINE__REAL(int, __fstat50, int a, void *b);
+  return _REAL(__fstat50, fd, buf);
+}
+
+DEFINE_INTERNAL(uptr, filesize, fd_t fd) {
+  struct stat st;
+  if (internal_fstat(fd, &st))
+    return -1;
+  return (uptr)st.st_size;
+}
+
+DEFINE_INTERNAL(uptr, dup2, int oldfd, int newfd) {
+  DEFINE__REAL(int, dup2, int a, int b);
+  return _REAL(dup2, oldfd, newfd);
+}
+
+DEFINE_INTERNAL(uptr, readlink, const char *path, char *buf, uptr bufsize) {
+  CHECK(&_sys_readlink);
+  return (uptr)_sys_readlink(path, buf, bufsize);
+}
+
+DEFINE_INTERNAL(uptr, unlink, const char *path) {
+  DEFINE__REAL(int, unlink, const char *a);
+  return _REAL(unlink, path);
+}
+
+DEFINE_INTERNAL(uptr, rename, const char *oldpath, const char *newpath) {
+  DEFINE__REAL(int, rename, const char *a, const char *b);
+  return _REAL(rename, oldpath, newpath);
+}
+
+DEFINE_INTERNAL(uptr, sched_yield) {
+  CHECK(&_sys_sched_yield);
+  return _sys_sched_yield();
+}
+
+DEFINE_INTERNAL(void, _exit, int exitcode) {
+  DEFINE__REAL(void, _exit, int a);
+  _REAL(_exit, exitcode);
+  Die();  // Unreachable.
+}
+
+DEFINE_INTERNAL(unsigned int, sleep, unsigned int seconds) {
+  struct timespec ts;
+  ts.tv_sec = 1;
+  ts.tv_nsec = 0;
+  CHECK(&_sys___nanosleep50);
+  int res = _sys___nanosleep50(&ts, &ts);
+  if (res)
+    return ts.tv_sec;
+  return 0;
+}
+
+DEFINE_INTERNAL(uptr, execve, const char *filename, char *const argv[],
+                char *const envp[]) {
+  CHECK(&_sys_execve);
+  return _sys_execve(filename, argv, envp);
+}
+
+tid_t GetTid() {
+  DEFINE__REAL(int, _lwp_self);
+  return _REAL(_lwp_self);
+}
+
+int TgKill(pid_t pid, tid_t tid, int sig) {
+  DEFINE__REAL(int, _lwp_kill, int a, int b);
+  (void)pid;
+  return _REAL(_lwp_kill, tid, sig);
+}
+
+u64 NanoTime() {
+  timeval tv;
+  DEFINE__REAL(int, __gettimeofday50, void *a, void *b);
+  internal_memset(&tv, 0, sizeof(tv));
+  _REAL(__gettimeofday50, &tv, 0);
+  return (u64)tv.tv_sec * 1000 * 1000 * 1000 + tv.tv_usec * 1000;
+}
+
+DEFINE_INTERNAL(uptr, clock_gettime, __sanitizer_clockid_t clk_id, void *tp) {
+  DEFINE__REAL(int, __clock_gettime50, __sanitizer_clockid_t a, void *b);
+  return _REAL(__clock_gettime50, clk_id, tp);
+}
+
+DEFINE_INTERNAL(uptr, ptrace, int request, int pid, void *addr, void *data) {
+  Printf("internal_ptrace not implemented for NetBSD");
+  Die();
+  return 0;
+}
+
+DEFINE_INTERNAL(uptr, waitpid, int pid, int *status, int options) {
+  CHECK(&_sys___wait450);
+  return _sys___wait450(pid, status, options, 0 /* rusage */);
+}
+
+DEFINE_INTERNAL(uptr, getpid) {
+  DEFINE__REAL(int, getpid);
+  return _REAL(getpid);
+}
+
+DEFINE_INTERNAL(uptr, getppid) {
+  DEFINE__REAL(int, getppid);
+  return _REAL(getppid);
+}
+
+DEFINE_INTERNAL(uptr, getdents, fd_t fd, void *dirp, unsigned int count) {
+  DEFINE__REAL(int, __getdents30, int a, void *b, size_t c);
+  return _REAL(__getdents30, fd, dirp, count);
+}
+
+DEFINE_INTERNAL(uptr, lseek, fd_t fd, OFF_T offset, int whence) {
+  CHECK(&__lseek);
+  return __lseek(fd, 0, offset, whence);
+}
+
+DEFINE_INTERNAL(uptr, prctl, int option, uptr arg2, uptr arg3, uptr arg4,
+                uptr arg5) {
+  Printf("internal_prctl not implemented for NetBSD");
+  Die();
+  return 0;
+}
+
+DEFINE_INTERNAL(uptr, sigaltstack, const void *ss, void *oss) {
+  DEFINE__REAL(int, __sigaltstack14, const void *a, void *b);
+  return _REAL(__sigaltstack14, ss, oss);
+}
+
+DEFINE_INTERNAL(int, fork) {
+  CHECK(&__fork);
+  return __fork();
+}
+
+DEFINE_INTERNAL(int, sysctl, const int *name, unsigned int namelen, void *oldp,
+                uptr *oldlenp, const void *newp, uptr newlen) {
+  CHECK(&__sysctl);
+  return __sysctl(name, namelen, oldp, (size_t *)oldlenp, newp, (size_t)newlen);
+}
+
+DEFINE_INTERNAL(uptr, sigprocmask, int how, __sanitizer_sigset_t *set,
+                __sanitizer_sigset_t *oldset) {
+  CHECK(&_sys___sigprocmask14);
+  return _sys___sigprocmask14(how, set, oldset);
+}
+
+DEFINE_INTERNAL(void, sigfillset, __sanitizer_sigset_t *set) {
+  DEFINE__REAL(int, __sigfillset14, const void *a);
+  (void)_REAL(__sigfillset14, set);
+}
+
+DEFINE_INTERNAL(void, sigemptyset, __sanitizer_sigset_t *set) {
+  DEFINE__REAL(int, __sigemptyset14, const void *a);
+  (void)_REAL(__sigemptyset14, set);
+}
+
+DEFINE_INTERNAL(uptr, clone, int (*fn)(void *), void *child_stack, int flags,
+                void *arg, int *parent_tidptr, void *newtls,
+                int *child_tidptr) {
+  Printf("internal_clone not implemented for NetBSD");
+  Die();
+  return 0;
+}
+
+}  // namespace __sanitizer
+
+#endif

lib/tsan/go/buildgo.sh

     ../../sanitizer_common/sanitizer_procmaps_common.cc
     ../../sanitizer_common/sanitizer_linux.cc
     ../../sanitizer_common/sanitizer_linux_libcdep.cc
+    ../../sanitizer_common/sanitizer_netbsd.cc
     ../../sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
   "
 elif [ "`uname -a | grep Darwin`" != "" ]; then